Aenert news. Invention analysis
Previously, in our article dated 08.09.2023 we have revised recent patents and patent applications related to heterocyclic-based liquid organic hydrogen carriers (LOHC) and technological aspects of their management. Now, in a brief review of recent inventions we will consider another popular carrier proposed as LOHC by key market players – aromatic compounds.
The collection of patent documents selected for this review is considered applicable to the field of LOHC based on aromatic carriers, although we should mention that this field is not exclusively limited by specific novel aromatic LOHC compositions – it also covers various technological aspects specific to such compositions, such as hydrogenation, dehydrogenation, catalysis, storage systems, etc. It is also worth mentioning that individual patent documents can propose a set or a combination of substances to be used as a hydrogen carrier, where apart from aromatic compounds, other substances may be encountered that can be attributed to other chemical groups, for instance, heterocyclic compounds and others.
Following we provide a list of the top applicants by their share in the patenting process in the field of aromatic-based LOHCs.

Applicants share in the intellectual property market, percentage. Patents, 2019-2023



Value: Market involvement ratio*; Y axis: Ownership ratio; Bubble size: Volume ratio.
*(Market involvement ratio = volume ratio multiplied by ownership ratio, where Volume ratio - share of applicant documents in total number of documents, Ownership ratio - applicant's participation share in total number of documents)

In the revised pool of patents, leading positions are taken by Sinopec China Petroleum & Chemical Corporation (CN) and its affiliated organizations, De Nora Permelec Ltd (JP), and Chiyoda Corporation (JP).

The largest patent family in the collection of documents examined for this review includes 31 patent documents and is represented by core document AU2020269473A1 (Core document is a base document for which a complete description of the invention is available in generally-accessible patent databases). It is followed by patent families with core documents US10450194B2 and US20200080212A1 (20 and 18 patent documents, respectively):

Organic hydrogen storage raw material dehydrogenation catalyst, carrier of the catalyst, hydrogen storage alloy, and method for providing high-purity hydrogen / A: AU2020269473A1 / IPC: C22C19/03, C01B3/56, C22C14/00, C22C23/06, C22C30/00 / LIN Wei; YANG Xue; SONG Haitao; SONG Ye; SUN Min; LIU Jun / Sinopec RIPP Research Institute of Petroleum Processing (CN); Sinopec China Petroleum & Chemical Corporation (CN) / Appl. date: 06.05.2020; Publ. date: 12.11.2020 / IP Australia / Core document: AU2020269473A1 / Technology categories: OAC, OHC / Technology elements: Hdh, Hct / Problems: EC, HCHD, LEHD / Technical solution types: M, C / Claims: 16 / Rating: 13; the most recent documents in this family were published on 21.10.2022 (CN111893360B) and 15.11.2022 (CN111892016B);

Liquid compounds and method for the use thereof as hydrogen stores / P: US10450194B2 / IPC: C01B3/38, C01B3/26, B01J19/24, C01B3/00, B60K15/03 / Boesmann Andreas; Wasserscheid Peter; Brueckner Nicole; Teichmann Daniel; Dungs Jennifer / Bayerische Motoren Werke Aktiengesellschaft (DE) / Appl. date: 27.05.2015; Publ. date: 22.10.2019 / United States Patent and Trademark Office / Core document: US10450194B2 / Technology categories: OAC / Technology elements: Hdh / Problems: EC, LEHD / Technical solution types: M / Claims: 11 / Rating: 16; the most recent documents in this family were published on 11.01.2022 (BR112015012183B1) and 08.09.2020 (CA2892228C);

Organic hydride production device / A: US20200080212A1 / IPC: C25B9/23, C25B3/25 / Mitsushima Shigenori; Nagasawa Kensaku; et al. / National University Corporation Yokohama National University (JP); De Nora Permelec Ltd (JP) / Appl. date: 18.11.2019; Publ. date: 12.03.2020 / United States Patent and Trademark Office / Core document: US20200080212A1 / Technology categories: OAC / Technology elements: ODD / Problems: HCC / Technical solution types: D / Claims: 4 / Rating: 10; the most recent documents in this family were published on 20.10.2022 (US20220333257A1) and 26.04.2022 (CA3064173C).

The following abbreviations are used in the documents hereinbefore and hereinafter: C - Composition; D - Device; M - Method; OAC - Arene/Aromatic compound; OHC - Heterocyclic; Hct - Catalyst; Hdh - Dehydrogenation; ODD - Organic carrier; EC - Ecological problems; HCC - High cost of compositions; HCHD - High cost of hydrogenation or dehydrogenation; LEHD - Low efficiency of hydrogenation or dehydrogenation.

In the revised collection of patent documents related to the use of aromatic compounds as liquid organic hydrogen carriers and associated technological processes and equipment, the most commonly encountered problems were LEHD - Low efficiency of hydrogenation or dehydrogenation, HLEC - High cost or low efficiency of catalyst, and EC - Ecological problems.

Generally, technical solutions disclosed in the patent documents under revision were represented in the form of methods. New devices and various compositions are proposed in a lesser, but still considerable number of documents.

Individual patented solutions of those collected for the present review were dedicated to new aromatic compounds to be used as liquid organic hydrogen carriers. The most popular carriers in the proposed formulations are benzene, toluene, dibenzyltoluene, benzyltoluene, and naphthalene, although about a dozen of other carriers is also proposed in the inventions.

Mostly, these patented solutions were attributed to the following IPC indices:
 

According to the International Patent Classification, the IPC indices above have the following definitions: B01J23/44 - Palladium; B01J23/46 - Ruthenium, rhodium, osmium or iridium; C01B3/00 - Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen; C01B3/22 - by decomposition of gaseous or liquid organic compounds; C01B3/24 - of hydrocarbons; C07C15/14 - all phenyl groups being directly linked; C07C15/16 - containing at least two phenyl groups linked by one single acyclic carbon atom; C07C5/10 - of aromatic six-membered rings; C07C5/367 - Formation of an aromatic six-membered ring from an existing six-membered ring, e.g. dehydrogenation of ethylcyclohexane to ethylbenzene; F17C11/00 - Use of gas-solvents or gas-sorbents in vessels.

In recent years, the majority of patent documents were registered in CNIPA (CN), USPTO (US), WIPO, KIPO (KR), and CIPO patent offices.

In the collection of recent patent documents disclosing novel compositions as LOHC, the most noticeable groups of inventions were those aimed at solving the problems of low hydrogen storage capacity of a carrier, poor hydrogen purity produced in the dehydrogenation process, and various problems related to ecological aspects. Below are some examples of recent patent documents that relate to these groups of technical solutions:

Patent application US20220033258A1 filed by Korea Research Institute of Chemical Technology (KRICT) (KR) and published on 03.02.2022 discloses a naphthalene-based hydrogen storage material. According to the invention, hydrogen is stored in a naphthalene-based compound corresponding to the Chemical formula 1 provided on the figure below. After the hydrogenation reaction, a compound presented as the Chemical formula 2 on the figure is formed. The claims of the invention also provide specific parameters of the hydrogenation and dehydrogenation process, such as types and amounts of catalysts used, process parameters, including temperature and pressure.
According to the authors of the invention, the proposed compound exhibits high hydrogen storage capacity. In addition, it uses a commercially-available and low-cost organic material, which makes it cost-effective.
The application belongs to a family comprising 4 patent documents published in 2022 in the USPTO, KIPO (KR), and EPO patent offices.



Image from: US20220033258A1

Patent application WO2022123166A1 published on 16.06.2022 by Arkema S.A. (FR) discloses a liquid hydrogen storage formulation comprising benzyltoluene (BT) in an amount of at least 50% (preferably at least 98%) of weight of the formulation, < 0.5 molar % (preferably, < 0.1%) of diphenylmethane (DPM) of the total number of moles, and at least one other LOHC fluid derived from petroleum or renewable products. The claims of the invention propose a set of LOHC fluids to be used: "…dibenzyltoluene, diphenylethane, ditolylether, phenylxylylethane, mono- and bi-xylylxylenes, 1, 2,3,4-tetrahydro-(1-phenyl - ethyl)naphthalene, di-isopropylnaphthalene, mono-isopropylbiphenyl, phenylethylphenylethane, N-ethylcarbazole, phenylpyridines, tolylpyridines, diphenylpyridines, dipyridylbenzenes, dipyridinetoluenes", their mixtures or combinations. Further the claims disclose a liquid hydrogen storage formulation comprising at least 50 wt % of benzyltoluene and dibenzyltoluene, preferably in the range of 70-99.9 wt % of benzyltoluene and 0.1-30 wt % of dibenzyltoluene.
The authors of the invention state that the proposed LOHC fluid can be used to produce hydrogen of high purity in the dehydrogenation process.
The application belongs to a patent family comprising 5 patent documents published between 2022 and 2023 in the FR, WO, CA, AU, and CN patent offices.

Patent application US20220109175A1 filed by Claire Technologies (US) and published on 07.04.2022 proposes a blendable LOHC composition comprising a primary component having a partially hydrogenated liquid organic compound with a cyclic structure. The composition further comprises a second LOHC composition having a secondary component consisting of a second liquid organic compound with a cyclic structure that is present at 0.1-25 wt % of the blendable liquid hydrogen carrier. Each of the primary and secondary components contain > 5 wt % labile hydrogen. The liquid organic compound is selected from "…benzene, toluene, xylene, xylol, dimethylbenzene, trimethylbenzene, naphthalene, benzyl-toluene, 1-methyl perhydro indole, 1,2-perhydrodimethyl indole, perhydro dibenzyl toluene, and all fully hydrogenated isomers thereof, and combinations thereof". The primary component is hydrogenated to contain 80 wt % - 99.9 wt % of the organic compound. The second LOHC composition comprises carbon from a carbon-neutral source. Claims of the invention further provide a system and method of generating hydrogen from the blended liquid organic hydrogen carrier.

The authors of the invention aim at reducing atmospheric emission of carbon oxides by the process.
The application is a part of a family comprising 5 patent documents published between 2022 and 2023 in US, WO, CA, AU, and EP.



Image from: US20220109175A1

108 - external source; 110 - storage vessel; 112 - feed line; 114 - pump; 116 - control valve; 118 - fresh LOHC feed; 120,124,174,190,196,212,262 - heat exchange unit; 122,266 - combustion exhaust gas; 126 - reactor effluent stream; 128 - reactor feed; 130 - reaction zone; 132 - catalyst containing reaction tubes; 144,254 - air; 146 - combustion chamber mixing box; 148 - combustion toluene; 150 - waste hydrogen; 152 - combustion chamber; 154 - combustion gases; 164 - shell side of reaction zone; 166 - temperature controller; 170 - incoming heated feed; 178 - cooled reactor effluent; 180 - fin-fan heat exchange unit; 184 - first separation unit; 186 - gaseous hydrogen; 188 - liquid toluene; 192 - refrigerant; 194 - refrigeration unit; 198 - second separation unit; 200 - hydrogen; 202 - toluene; 204 - charcoal filer; 206 - purified hydrogen stream; 208 - hydrogenation reactor effluent; 210 - hydrogenation reactor; 218 - fin-fan heat exchanger; 220 - anode gas hydrogen recycle stream; 222 - anode circulating compressor; 224 - electrochemical conversion device; 226 - anode side; 228 - cathode; 230 - electrolyte layer; 232 - external wiring; 236,270 - stream; 238 - spent fuel portion; 240 - fresh feed portion; 242 - removal; 244 - bleed stream; 250 - anode exhaust stream; 252 - cathode exhaust stream.

By the Editorial Board